Hot runner detection and response systems, devices, and methods

ABSTRACT

Various systems, devices, and methods for detecting and/or responding to the temperature of brakes are disclosed. Certain embodiments relate to inhibiting or preventing the overheating of the brakes of such vehicles, such as could occur when a hot runner condition is present.

INCORPORATION BY REFERENCE OF ANY PRIORITY APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/416,661, filed on May 20, 2019, which is acontinuation application of U.S. patent application Ser. No. 15/268,179,filed on Sep. 16, 2016, which claims priority to Italian PatentApplication No. 102015000052631, filed on Sep. 17, 2015, the disclosuresof which are incorporated herein by reference. All applications forwhich a foreign or domestic priority claim is identified in theApplication Data Sheet as filed with the present application are herebyincorporated by reference under 37 CFR 1.57.

BACKGROUND Field

The present disclosure relates to systems, devices, and methods fordetecting and/or responding to the temperature of brakes, such asbraking devices for heavy vehicles. Certain embodiments relate toinhibiting or preventing the overheating of the brakes of such vehicles.

Description of Certain Related Art

A braking unit is a mechanical apparatus that diverts energy from amoving system, thereby reducing the motion of the moving system. Abraking unit is typically used for slowing or stopping a moving vehicle,such as by friction between a generally non-rotating brake pad and arotating brake disk or drum. The brake pad can be pressed against thebrake disk or drum by a brake caliper.

SUMMARY OF CERTAIN EMBODIMENTS

A problem associated with braking units occurs when the brake pad is inunintentional contact with the brake disk or drum. For example, amalfunction may cause the brake caliper to lock-up against the disk ordrum, resulting in an unwanted continuous braking condition. Theconstant friction between the disk and the brake pad can result inexcessive heating, which can cause serious damage to the braking unitand/or other components (e.g., can cause bursting of the tire on thewheel with the malfunctioning brake). This problem is called a “hotrunner.” The problem of hot runners can be particularly significantwithin the context of heavy vehicles, such as articulated vehicles, dueto the heavy loads, high energies, and conditions in which such vehiclesare often operated. This problem can be further exacerbated underconditions that are demanding for the braking unit, such as whendescending a prolonged downward grade.

Various embodiments disclosed herein relate to hot runner detection andresponse systems, devices, and methods, such as systems and forinhibiting or preventing the overheating of the brakes of vehicles, suchas heavy vehicles. Certain embodiments disclosed herein provide abraking unit for heavy vehicles. Some embodiments provide a method forinhibiting or preventing the overheating of the brakes on a heavyvehicle when traveling. Some variants provide a simple and reliablesystem for reducing or preventing the hot runners phenomenon. Certainimplementations improve heavy vehicle road safety. Various embodimentsprovide a safety system that is capable of detecting and/or predictingthe initial phases of the hot runners phenomenon. Some embodimentsinclude providing a timely warning (e.g., to the driver, to anotheruser, or to another computing system) to reduce the danger associatedwith hot runners.

Some vehicle braking units include a braking device, such as a brake padcomprising one or a plurality of sensors. For example, the brake pad caninclude at least one piezoceramic sensor that is configured to operateat high temperatures and/or to emit an electrical signal when subjectedto mechanical stress. The brake pad thus structured is able to detect ina simple and economical way, without the need for an external energysource, the presence and extent of the mechanical stresses which canarise at the interface between the pad and the brake disk. Such a brakepad can allow for the possibility of monitoring the braking, such as toreduce or eliminate phenomena (e.g., vibrations and noise) and/or toreport abnormal operating conditions.

Certain embodiments disclosed herein relate a braking unit for heavyvehicles. The braking unit can include braking devices. Each brakingdevice can include at least one brake shoe or brake pad associated witha wheel of the heavy vehicle. The pad or shoe can have a support and ablock of friction material configured to act upon a brake disk or brakedrum. The brake pad can include at least one temperature sensor locatedbetween the block of friction material and the support. The temperatureof the brake pad is typically representative of the brake operatingtemperature. Moreover, obtaining the temperature datum from anon-rotating part of the brake system (e.g., the brake pad) avoids otherlimitations that are typical of measurements taken on rotating bodies,such as disk brakes or drum brakes, that render measurement complex andcostly.

The brake pad can include a safety device for inhibiting or preventingthe overheating of the brakes. The safety device can have one or morealarm units and one or more control units. The control units cancommunicate with the at least one sensor and/or with the alarm unit. Thecontrol units can have a memory comprising a first temperaturethreshold. In some embodiments, if the temperature detected for at leastone brake pad or brake shoe is higher than the first temperaturethreshold, then an alarm signal is emitted. The control units caninclude a comparator that is configured to validate the emission of thealarm of a condition is met. For example, the condition can be that thetemperature detected for at least one brake pad or brake shoe is higherthan the first temperature threshold and the temperature detected for atleast one other brake pad or brake shoe is lower than the firsttemperature threshold.

In some embodiments, the comparator is configured for substantiallyreal-time comparison of the temperatures detected at the brake pads orbrake shoes. In some embodiments, the comparator is configured tovalidate the emission of the alarm if the temperature detected for atleast one brake pad is higher than the first temperature threshold andif the temperature detected for the certain number or amount (e.g., amajority) of the brake pads is lower than the first temperaturethreshold.

In some embodiments, the memory comprises a second temperature thresholdthat is lower than the first temperature threshold, the control unitsbeing configured to drive the emission of a pre-alarm if the temperaturedetected for at least one brake pad or brake shoe falls between thefirst and the second temperature thresholds. In some implementations,the alarm unit is configured for the emission of an acoustic and/oraudible alarm.

In some embodiments, the control units comprise peripheral electroniccontrol units each located at a respective brake and a centralelectronic control unit communicating with the peripheral control unitsand with the alarm unit. In some embodiments, the control units comprisea central electronic control unit communicating with the at least onesensor and with the alarm unit. In some embodiments, the control unitsare connected to a CAN-bus (Controller Area Network) of the vehicle.

In some embodiments, the brake pad comprises at least one ancillarysensor located between the block of friction material and the supportand communicates with the control units, the at least one ancillarysensor comprising at least one pressure sensor and/or one shear sensor.In some embodiments, the pressure sensor and the shear sensor arepiezoceramic sensors which differ in regard to the direction of theapplied bias therein.

In some embodiments, the comparator is configured to validate theemission of the alarm only in the presence of a predeterminedcorrelation between the temperature signal and the signal produced bythe at least one ancillary sensor within a predetermined measurementinterval of time.

In some embodiments, each sensor is covered by an electricallyinsulating protective layer. In certain embodiments, the control unitscomprise an electrical power supply that is configured to absorb energyfrom the motion of the vehicle.

Some embodiments of the invention comprise a method for inhibiting orpreventing the overheating of the brakes on a heavy vehicle. Each brakecan comprise at least one brake pad or a brake shoe having a support anda block of friction material acting upon a brake disk or brake drumassociated with a wheel of the heavy vehicle, at least one temperaturesensor located between the block of friction material and the support.The method can include acquiring (e.g., in real time or after a timedelay) the temperature detected at the brake pads or brake shoe. Themethod can include comparing (e.g., in real time or after a time delay)the temperature detected at the brake pads or brake shoes. The methodcan include validating the emission of an alarm. For example, thevalidation can occur in response to the temperature detected for atleast one brake pad or brake shoe being higher than the temperaturethreshold and the temperature detected for at least one brake pad orbrake shoe is lower than the temperature threshold. The method caninclude, in response to the validation occurring, generating an acousticand/or visual alarm.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features and benefits of the invention will become furtherevident from the description below, which relates to certainnon-exclusive embodiments of braking systems, devices, and methods forinhibiting or preventing the overheating of the brakes on a heavyvehicle. These and other features are illustrated by way of certainnon-limiting examples in the accompanying drawings, in which:

FIG. 1 illustrates a perspective view of a heavy vehicle;

FIG. 2 illustrates a side view of a braking unit, such as a braking unitof the heavy vehicle of FIG. 1 ;

FIG. 3 schematically illustrates a perspective view of a braking device;

FIG. 4 illustrates a perspective view of the braking device of FIG. 3without the block of friction material;

FIG. 5 schematically illustrates an embodiment of a hot runner detectionand response system;

FIG. 6 schematically illustrates another embodiment of a hot runnerdetection and response system;

FIG. 7 illustrates a diagram of a brake pad of the system of FIG. 6 ;

FIG. 8 illustrates a chart of the temperature of a disk brake and thetemperature of a brake pad; and

FIG. 9 schematically illustrates a method of detecting and responding toa hot runner.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

Embodiments of systems, components, and methods will now be describedwith reference to the accompanying figures, wherein like numerals referto like or similar elements throughout. Although several embodiments,examples and illustrations are disclosed below, the inventions describedherein extends beyond the specifically disclosed embodiments, examples,and illustrations. The inventions disclosed herein can include otheruses of the inventions and obvious modifications and equivalentsthereof. The terminology used in the description presented herein is notintended to be interpreted in any limited or restrictive manner simplybecause it is being used in conjunction with a detailed description ofcertain specific embodiments of the inventions. Embodiments of theinventions can comprise several novel features. No single feature issolely responsible for its desirable attributes or is essential topracticing the inventions herein described.

Overview

FIG. 1 illustrates an example of a heavy vehicle V. A heavy vehicle caninclude, for example, an articulated vehicle, tractor-trailer (alsocalled a tractor-trailer, semi, big rig, eighteen-wheeler, orotherwise), tank truck, box truck, flatbed truck, wrecker truck, garbagetruck, cement truck, dump truck, grader, backhoe, front loader, miningtruck, etc. In some implementations, a heavy vehicle (including atrailer, if any) has a maximum weight of at least 80,000 lbs. and/or anallowable length of at least 18 meters.

FIG. 2 shows a braking unit 1100 of a vehicle, such as the heavy truckshown in FIG. 1 . The braking unit 1100 can include a caliper 1102 and adisk shaped rotor 1103 rotating about an axis of the wheel of thevehicle. The braking unit 1100 can include a braking device 101, such asa brake pad or brake shoe. Two opposite braking devices 101 are movableby a corresponding piston 1104 so that friction material 103 thereof mayengage or disengage the opposite sides of the disk shaped rotor 1103.Signals coming from one or both braking devices 101 can be transmittedvia cables 1105 to a processing unit 1107, which can include a signalconditioning device comprising analog front ends 1106 anddigitalization. As will be discussed in more detail below, signals fromthe braking devices 101 can be used to aid in detecting and/orresponding to a hot runner situation, which could occur if one or bothof the braking devices 101 were in continuous and/or unintentionalcontact with the rotor 1103, and which could result in substantialdetrimental heat generation.

Braking Devices with Sensors

FIGS. 3 and 4 illustrate the braking device 101. For purposes ofpresentation, the braking device 101 shown in the figures, and discussedbelow, is described as a brake pad. However, the braking device 101 cantake many other forms, such as a brake shoe or otherwise.

As shown, the brake pad 101 comprises a support element 102, which canbe called a a “backplate.” The backplate is preferably but notnecessarily metallic. The brake pad 101 can include a block of frictionmaterial 103 supported by the support element 102. The brake pad 101 caninclude one or more sensors 104, such as piezoceramic sensors. Thesensors 104 can be supported by the support element 102. The sensors 104can be interposed between the support element 102 and the block offriction material 103. As shown, the piezoceramic sensors 104 can besupported in a raised arrangement on the support element 102.

The support element 102 in particular is shaped as a contour shaped flatplate having a first main planar surface 105 that is intended in use toface an element to be braked, such as a vehicle brake disc, and a secondmain planar surface 106 that is parallel to the first main planarsurface 105. The block of friction material 103 has, in particular, afirst main planar surface 107 that is conjugated to the first planarsurface 105 of the support element 102 and a second planar surface 108that is parallel to the first planar surface 107, and intended in use todirect contact with the element to be braked.

The piezoceramic sensors 104 are able to detect the forces that areexchanged in use during the contact between the brake pad 101 and theelement to be braked as a result of their inherent ability to emit anelectrical signal when subjected to a mechanical stress. As shown, thesupport element 112 supports an electrically insulated electricalcircuit 109. The circuit 109 has electrical contacts to which electrodesof the piezoceramic sensors 104 are connected. The electrical circuit109 receives and transmits electrical signal, which is generated withoutthe need for an electrical power supply from piezoceramic sensors 104,when they are subjected to a mechanical stress in the direction ofpolarization. The electrical signal emitted by the piezoceramic sensors104 and collected by the electrical circuit 109 can either be processedin real time or at a later point in time.

The piezoceramic sensors 104 are made of piezoceramic materials with aCurie temperature greater than 200° C. and are formed of a preferablycylindrical body that is polarized in the direction of its axis anddelimited by a pair of opposite flat faces that are arranged in useparallel to the main planar surfaces of the support element 102.Preferably only one of the faces, in particular, the one facing theelectrical circuit 109, has both of the electrical signal samplingelectrodes. Specific examples of piezoceramic sensors 104 that may beused are, for instance, PIC 255 (Manufacturer: PI Ceramic), PIC 300(Manufacturer: PI Ceramic), PIC 181 (Manufacturer: PI Ceramic), PIC 050(Manufacturer: PI Ceramic), TRS BT200 (Manufacturer: TRS Ceramics),PZT5A1 (Manufacturer: Morgan Advanced Ceramic), PZT5A3 (Manufacturer:Morgan Advanced Ceramic).

The electrical circuit 109 has branches that are suitably shaped inorder to arrange the piezoceramic sensors 104 in discrete positions onthe support element 102 and is also provided with an integratedelectrical connector at the edge of the support element 102.

In some embodiments, one or more temperature sensors and/or one or moreshear force sensors that are electrically connected to the electricalcircuit 109 may be mounted on the support element 102. The electricallyinsulated electrical circuit 109 is preferably screen printed andapplied directly onto the support element 102.

In certain implementations, some or all of the sensors on the supportelement 102 are installed onto the electrically insulated electricalcircuit 109 from the side of the latter that faces the block of frictionmaterial 103. The sensors that are thus integrated into the supportelement 102 are highly capable of measuring the forces acting on thebrake pad 101 during braking or in general during the running of thevehicle.

A damping layer 1101 (see FIG. 2 ) can be provided that is interposedbetween the block of friction material 103 and the support element 102.The damping layer 1101 can have a first main surface that is conjugatedto the first planar surface of the support element 102 and a secondsurface that is conjugated to the first planar surface of the block offriction material 103. The damping layer 1101 can be mostly made ofphenolic resin material.

In some configurations, each piezoceramic sensor 104 is embedded withina protective element 116. The protective element 116 can be located onthe support element 102 at the position of the piezoceramic sensor 104.For the electrical insulation of the piezoceramic sensor 104 theprotective element 116 can be made of electrically insulating material.

The protective element 116 can have mechanical properties, such as anelastic modulus that has been carefully chosen in order to limit theforce transmitted to the piezoceramic sensor 104 when an externalcompression force is applied to the block of friction material 103.Further details regarding this and other aspects of the brake pad can befound in International Application No. PCT/IB2013/060881, filed Dec. 12,2013 and U.S. patent application Ser. No. 15/184,806, filed Jun. 16,2016, the entirety of each of which is hereby incorporated by referenceherein.

The protective element 116 can be configured to direct at least part ofthe external compression force to an area of the support element 102surrounding the piezoceramic sensor 104 itself. This can be beneficialbecause, for example, a considerable external compression force is infact generated during the hot pressing of the block of friction materialonto the support 102.

In various embodiments, the protective element 116 substantially orcompletely embeds the piezoceramic sensor 104. The protective element116 can be made of a resin-based material, for example, the material forthe protective element can include one or more of: polyimide resins,epoxy resins (loaded or not), Bismaleimide resins, and Cyanate-Esterresins. In certain implementations, the protective element can be madeby dripping the material at a standard pressure and moderatetemperatures (such as less than about 200° C.) prior to forming theblock of friction material 103. Ceramic materials that are much harderthan resins and suitable for temperatures above 350° C. may however alsobe used for the protective element.

In some embodiments, some or all of the sensors and/or other componentsof the electrical circuit 109 have a respective protective element, suchas a protective element of the same type as that described above. Invarious embodiments, due to the protection provided by the protectiveelement 116, the forces actually experienced by the sensors during theproduction of the brake pad 101 or when the brake unit is in operationis reduced.

Certain Hot Runner Detection and Response Systems

FIG. 5 schematically illustrates a system for detecting and/orresponding to overheated braking components, such as may occur during ahot runner condition. As shown, the system can include sensors (Sp1 andSp2), which can be integrated into respective brake pads. The system caninclude ECU (Electronic Control Units), which can acquire analog signalsfrom the sensor and digitalize and process the signals to detect hotrunners. The system can include a sensor gateway, which can receivealarms and/or data from the ECUs. The system can include a mediainterface, which can receive alarms and/or data from the gateway. Insome embodiments, the media interface can provide a human interface,such as delivering data and/or alarms for hot runners to a user (e.g., adriver) by visual and audio messages.

FIG. 6 schematically illustrates another system 1 for detecting and/orresponding to overheated braking components, such as overheating thatmay occur during a hot runner condition. As will be described in moredetail below, the system 1 can reduce or eliminate overheating inbraking unit, such as braking units for heavy vehicles. As will bediscussed in more detail below, in various embodiments, the system 1 canbe configured to detect when a hot runner condition is present in atleast one wheel of a vehicle, such as a heavy vehicle. In certainimplementations, the system 1 can be configured to respond to a hotrunner condition being detected, such as by sending an alert to a user,to an on-board or off-board computer system, or otherwise.

As illustrated, the system 1 can include one or more of the brake units1100. As described above, the brake units 1100 can comprise a caliperwith two brake pads 101 that can be activated onto a disk brake. In somevariants, the brake units 1100 comprise brake shoes that can beactivated against a drum brake.

FIG. 7 illustrates a schematic side view of the brake pad 101, which canbe identical or similar to the brake pad 101 described above. As shown,the brake pad 101 can have a support 102 and a block of frictionmaterial 103 connected with the support 102 and configured to act uponthe associated disk brake. The brake pad 101 components can be designedfor use at high temperatures. For example, the components can beconfigured to operate at a temperature of at least about 600° C.

The brake pad 101 can include one or more sensors 104A, 104B interposedbetween the support 102 and the block of friction material 103. Thesensors 104A, 104B can be mounted onto an electrically insulatedelectrical circuit 109 designed to acquire the electrical signalsemitted by the sensors 104A, 104B to be processed either in real time orat a later time. The electrical circuit 108 can be integrated into thesupport 102, such as by heat resistant screen printing technology (e.g.,glass ceramic material). The sensor 104A can comprise a temperaturesensor, such as PT1000 sensors. In some embodiments, the brake pad 101includes only one temperature sensor 104A. In certain variants, thebrake pad 101 comprises a plurality of temperature sensors 104A. In someembodiments, the sensor 104B comprises an ancillary sensor, such as apressure sensor (e.g., a piezoceramic pressure sensor) and/or a shearsensor (e.g., a piezoceramic shear sensor). Some embodiments compriseonly one sensor 104B. Some variants include a plurality of the sensors104B. The sensors 104A, 104B and the electrical circuit 109 can becovered by a protective element 116 (also called a protective layer).The protective layer can be made of electrically insulating material. Insome embodiments, the protective layer comprises a ceramic material.

With regard to FIG. 6 again, the system 1 can include control units 11,12. In some embodiments, the control unit 11 comprises a peripheralcontrol unit and the control unit 12 comprises a central control unit.Various embodiments have one or more of the peripheral control units 11and/or the central control unit 12. For example, the system 1 caninclude 1, 2, 3, 4, 5, 6, 7, 8, or more peripheral control units 11and/or 1, 2, 3, 4, 5, 6, 7, 8, or more central control units 12. In someembodiments, the peripheral control units 11 can be located at or near arespective brake and/or at or near a respective wheel. For example, thesystem 1 can include at least one peripheral control unit 11 for eachwheel. Some embodiments include at least one peripheral control unit 11for each set of wheels on the end of an axle, such as one peripheralcontrol unit 11 for each of the pairs of rear trailer wheels shown inFIG. 1 . In certain embodiments, the central control unit 12 is locatedin a place that is centralized on the vehicle and/or in a place tofacilitate service or connection with other components. For example, thecentral control unit 12 can be located in or near a vehicle on-boardelectronic system, such as an electronic control unit (ECU). The centralcontrol unit 12 does not need to be centrally located, such as inrelation to the vehicle overall, the positioning of the peripheralcontrol units 11, the sensors, the wheels, or otherwise.

The peripheral control units 11 can be configured to communicate (e.g.,receive signals from) the sensors 104A, 104B of the brakes pads 101. Forexample, the peripheral control units 11 and sensors 104A, 104B cancommunicate by a communication interface 8 on the brake pad and acorresponding communication interface 19 on the brake pads 101. In someembodiments, the interface 8 comprises an electrical connector. In somevariants, the interface 8 comprises a wireless connection (e.g., RFtransmitter and receiver). The connector can be configured toelectrically couple with the electrical circuit 109. The connector 109can be configured to transmit electrical signals from the sensors 104A,104B to one or more components on the outside of the brake pad 101(e.g., the unit 11) for processing.

The peripheral control unit 11 can comprise a memory 13, a processor 20,and an electrical power supply 21. The peripheral control unit 11 canhave an A/D digitization stage 22 that transforms the analog signalsfrom the sensors 104A, 104B into digital signals. The peripheral controlunit 11 can have a digital signal conditioning stage 23. The processor20 of the peripheral control unit 11 can be programmable to process theincoming digital signals. In some embodiments, the peripheral controlunit 11 is configured to generate an alarm or pre-alarm drive signal tobe sent to the central control unit 12, as is discussed in more detailbelow. As illustrated, the peripheral control unit 11 can be connectedwith the central control unit 12, such as through communicationinterfaces 15, 16. The communication interfaces can comprise a wiredconnection (e.g., an electric cable) or a wireless connection (e.g., RFtransmitter and receiver).

In certain embodiments, the central control unit 12 is configured toconcentrate and/or convert the information received from peripheralcontrol units 11 and/or to transmit information to the CAN-bus of thevehicle, such as, for communication with the ECU of the vehicle. Thecentral control unit 12 can include a memory 24 and an electrical powersupply 29. The memory 24 can be used to store information received fromthe peripheral control unit 11 or other information, such as programinstructions, threshold values, etc. In some embodiments, the memory 24contains at least one first threshold temperature. In some variants, thememory 13 of the peripheral control unit 11 contains the first thresholdtemperature.

As shown, the system 1 can include a comparator 14. In the illustratedembodiment, the comparator 14 is located in the central control unit 12,though in other embodiments the comparator 14 is located additionally oralternatively in one or more of the peripheral control units 11. Thecomparator 14 can be configured to determine and/or validate whether thetemperature detected for at least one brake pad 101 exceeds the firstthreshold temperature. In some embodiments, the first thresholdtemperature is at least about: 300° C., 350° C., 400° C., 450° C., 500°C., 550° C., 600° C., temperatures between the aforementionedtemperatures, or other temperatures. The comparator 14 can be configuredto determine whether the temperature detected for at least one other ofthe brake pads 101, and preferably for a majority of the other brakepads 101, is below the first threshold temperature. The comparator 14can be configured for the real-time or non-real-time comparison of thetemperatures detected for the brake pads 101. In some embodiments,depending upon the outcome of the comparison, the comparator 14 performsthe validation or otherwise of the emission of an alarm. In someembodiments, the comparator 14 performs the validation immediately; inother embodiments the comparator 14 performs the validation after a timedelay.

In some embodiments, the memory 13 and/or the memory 24 comprises asecond temperature threshold that is less than the first temperaturethreshold. In some embodiments, the second threshold temperature is atless than or equal to about: 200° C., 250° C., 300° C., 350° C., 400°C., 450° C., temperatures between the aforementioned temperatures, orother temperatures. The comparator 14 can be configured to determinewhether the temperature detected for at least one of the brake pads 101is between the first and second temperature thresholds. If so, someembodiments generate a pre-alarm drive signal.

The central control unit 12 can be programmable to receive and/orvalidate the alarm drive signal and/or the pre-alarm drive signal fromone or more of the peripheral control units 11. In some implementations,the central control unit 12 is configured to automatically convert thealarm drive signal into an activation signal. The central control unit12 can be configured to automatically translate the pre-alarm drivesignal into a pre-alarm activation signal. The activation signal and/orthe pre-alarm activation signal can be received by an alarm unit 10 ofthe system 1. The alarm unit 10 can be configured to communicate withthe central control unit 12 via communication interfaces 17, 18. Thecommunication interfaces 17, 18 can be cabled or wireless.

The alarm unit 10 can be part of a safety feature of the system 1. Thesafety feature can be configured to detect, inhibit, and/or preventoverheating of the brakes. In some embodiments, the safety featureincludes the alarm unit 10 and one or more of the control units 11, 12,which communicate with the sensors 104A, 104B. In various embodiments,at least one of the components of the safety feature are configured tocommunicate with one or more systems of the vehicle, such as with theECU of the vehicle via the CAN-bus or otherwise.

As previously mentioned, the peripheral control unit 11 can beprogrammable to generate an alarm or pre-alarm drive signal to be sentto the central control unit 12, and the central control unit 12 can beconfigured to convert the drive signal into an activation signal of thealarm unit and/or to translate the pre-alarm drive signal into anactivation signal of an alarm unit 10. The central control unit 12, inthe case of validation, can activate the alarm unit 10 in order to emita first alarm signal. In some embodiments, the activation is performedimmediately; in other embodiments the activation occurs after a timedelay. The alarm unit 10 can be configured for the emission of a visualand/or audible alarm that can be perceived within the vehicle. Forexample, the alarm unit 10 may include lights (e.g., LEDs) and/orbuzzers, such as on the instrument panel of the vehicle. Alternatively,or additionally, the alarm unit 10 can be configured to transmit analarm to a user interface (e.g., such as to the driver or another user'ssmartphone and/or to an off-board computerized fleet management system).The system 1 can include or interface with wireless communicationhardware or software to transmit the alarm. In this way, the operatingmalfunction of the braking unit is promptly noticed by the driver whocan then take the necessary timely actions to reduce or eliminate themalfunction before the onset of catastrophic events. For example, thedriver can slow or stop the vehicle to allow the temperature of thebrake units 1100 to decrease and/or can arrange for maintenance of themalfunctioning brake unit 1100. In some implementations, in response tothe alarm, an automatic reaction of the vehicle can occur, such as thevehicle stopping or its maximum speed being reduced. In someembodiments, the alarm is sent to the ECU of the vehicle, which can beprogrammed to automatically take an action in response.

This is of course just one example among the various possibleconfigurations for the control units 11, 12. Another possibleconfiguration has a single peripheral control unit 11 for handling thesensors 104A, 104B of all of the brakes. In another contemplatedvariation, the central control unit 12 integrates all of the functionsincluding those of the peripheral control units 11. For example, thecentral control unit 12 can be connected with the brake pads 101 withouta separate intervening peripheral control unit 11. Some embodimentsinclude a plurality of peripheral control units 11, each located at arespective wheel of the vehicle. This can be beneficial since eachperipheral control unit 11 can be located at or near its respectivewheel. Some variants include a single peripheral control unit 11, whichcan be beneficial in consolidating components and functionality and/orby positioning the peripheral control unit 11 in a central locationbetween the wheels. In some implementations, the vehicle CAN-bus can beconnected to the peripheral control units 11 in addition to, or insteadof, the central control unit 12. In any case, the connection to theCAN-bus can be achieved by radio links such as Bluetooth, Wi-Fi or otherradio protocols and standards based upon RF technology.

In some implementations, the electrical power supplies 21, 29 areconfigured to harvest and/or absorb energy from the motion of thevehicle, such as in the form of vibrational, kinetic, and/or thermalenergy that can be converted into electrical energy. The electriccomponents of the system 1 (e.g., the controllers 11, 12) can be poweredby the electrical energy converted from the energy absorbed from themotion of the vehicle. In some embodiments, the energy harvestercomprises a piezoelectric crystal, thermoelectric generator, orotherwise. The electrical energy can be stored in a storage device, suchas a battery or capacitor.

Certain Hot Runner Detection and Response Methods

Various hot runner detection and response methods are described below.In some embodiments, the methods are based upon the sensors 104A, 104Bmounted on the brake pads 101. Certain embodiments take advantage of thefact that there is typically a strong correlation between thetemperature distribution over the disk brakes and the brake pad 101where the temperature sensors 104A are installed. An example of suchcorrelation is shown in FIG. 8 , which plots the temperature of a diskbrake and the temperature of a brake pad. It is known that the brakedisk temperature (and therefore also that of the brake pad) caninfluence the appearance of hot runners and the relative increase inthis value is a typical side effect of the hot runners phenomenon. Inthe event of a hot runner condition, the brake disk temperature andtherefore the temperature of the brake pad 101 tends to rise in anabnormal manner and very quickly up to limiting values (even above 600°C.). Thus, it can be beneficial to monitor the temperature of the brakepad 101 and/or to detect a hot runner.

In some embodiments, to reduce or avoid false alarms, it is useful toadopt a more sophisticated strategy for discriminating a hot runner froma normal rise in temperature due, such as may occur during prolonged useof the braking unit, for example, when traveling through longmountainous sections of road, especially downhill, which involves veryhigh braking unit temperatures without there being an actual malfunctionof the braking unit itself. In some embodiments, the ancillary pressuresensors 104B or shear sensors are used, in conjunction with an analysisbased upon the temporal flow of data, preferably in real time, andcorrelations between the temperature and pressure data or braking torquedata. For example, a period of time T is appropriately set such that itis long enough for the phenomena identified by the analysis carried outwithin this period T not to be confused with those phenomena that aretypical of normal braking that normally lasts much less than a minute.In some embodiments, the period T equal to a length of at least about: 5minutes, 10 minutes, 15 minutes, time values between the aforementionedvalues, or other time values. The period T can be short enough to allowfor the detection of hot runners sufficiently early to limit or nullifythe damage associated with the hot runners.

In some implementations, the logic for the activation of an alarm signalis based upon the definition of two logic functions H(t) and G(t). Thesefunctions are as follows within the period T:H(t)=−1 if P<P _(threshold);H(t)=1 elsewhere;G(t)=−1 if T<T _(threshold1); andG(t)=1 elsewhere.

In which:

P is the brake pressure as measured by the pressure sensors 104B (or byother sensors on board the vehicle); and

T is the temperature measured by the temperature sensors 104A.

In some embodiments, P_(threshold) is about 10 bar and/or T_(threshold1)is at least about 500° C. or at least about 600° C. In someimplementations, the pressure P is the pressure measured at the caliper.In certain embodiments, the pressure P is the pressure measured at thebrake pad 101. In certain variants, in place of the pressure P, thetorque T can also be used with identical or similar logic and anidentical or similar threshold value.

Thanks to the calculation of the correlation between the two functionswithin the period T by the following integral I:

$I = {\frac{1}{\tau}{\int_{0}^{T}{{G(t)}{H(t)}{dt}}}}$

It is possible to obtain a condition that depends upon the correlationof the two functions G(t) and H(t). In fact, under normal workingconditions (without the presence of hot runners) it is expected that thetwo functions will be highly correlated, which means in numerical termsthat the integral of I=1 or very close to it. In the presence of a hotrunner at a wheel the integral of I is consistently less than 1. Infact, in the absence of braking during the period T, I=−1. A conditioncan therefore be determined for the presence of hot runners by settingan appropriate threshold that is low enough for I, being identified asthe threshold for generating an alarm activation signal for the presenceof a hot runner.

In some embodiments, the threshold may be set as I_(threshold)<0. Whenthis condition is true over the period T, this can indicate the presenceof a hot runner. This would mean having more than 50% of the period Tresulting in no correlation between the brake pad temperature andpressure. In certain implementations, to reduce or avoid the occurrenceof false alarms, fuzzy logic may be applied to determine theintermediate degrees of probability of the presence of a “hot runnerevent”. The logic can include a cross-check between the I values amongthe various brake pads. In some situations, if all or the majority ofthe pads are over I_(threshold) then the presence of a hot runner ismore likely.

In some embodiments, a method for detecting and/or responding to a hotrunner includes determining whether, for at least one brake pad, whetherT>T_(threshold1). If so, the method can include generating a pre-alarmdrive signal. The pre-alarm drive signal can be automatically convertedinto an activation signal for the alarm unit 10, which emits apre-alarm. For example, a first type of warning (e.g., a chime and/orlight) can be activated. In some embodiments, the method includesdetermining, for at least one brake pad, whether T>T_(threshold1) andI<0. If so, the method can include generating an alarm drive signalindicating the presence of a hot runner. In some embodiments, the methodincludes determining whether the alarm activation signal is not detectedby any additional brake pads 101, such as by a majority of the brakepads 101. If so, then the alarm activation signal can be found to bevalidated. The alarm activation signal can be converted into anactivation signal for the alarm unit 10, which can emit an alarmindicating the presence of a hot runner. For example, a second type ofwarning (e.g., a chime and/or light) can be activated.

In certain implementations, a method for detecting and/or responding toa hot runner includes the use of temperature data only. In some suchembodiments, the correlation is examined between the temperatures of thebrake pads 101 during the period T. The method can include determiningwhether a second temperature threshold (e.g.,T_(threshold2)<T_(threshold1)) is established. In some embodiments, themethod includes determining whether, for at least one brake pad 101,whether T>T_(threshold2) and <T_(threshold1). If so, then a pre-alarmdrive signal can be generated. The pre-alarm drive signal can beautomatically converted into an activation signal for the alarm unit 10,which emits a pre-alarm, such as activating a chime or light. In someembodiments, the method includes determining, for at least one brake pad101, whether T>T_(threshold1). If so, then an alarm activation signalcan be generated indicating the presence of a hot runner. In someembodiments, the method includes determining whether the alarmactivation signal has been detected for others of the brake pads, suchas a majority of the brake pads 101. If so, then the alarm activationsignal can be considered validated. The alarm activation signal and canbe converted into an activation signal for the alarm unit 10, which emitan alarm indicating the presence of a hot runner, such as activating achime or light.

FIG. 9 illustrates another method for detecting and/or responding to ahot runner. As shown, the method can begin at a main cycle. The methodcan include receiving a temperature value T. Some embodiments includedetermining whether the value T is valid, such as whether thetemperature is within the expected ranges of possible temperatures. Ifno, then the method returns to the main cycle. If yes, then the methodproceeds. The method can include determining whether theT>T_(threshold1). If no, then the method returns to the main cycle. Ifyes, then the method proceeds. The method can include transmitting afirst alarm to indicate that an excessive temperature has been detected.The method can include determining whether I<0. If no, then the methodreturns to the main cycle. If yes, then the method proceeds. The methodcan include transmitting a second alarm, which can indicate that a hotrunner has been detected.

Some methods and systems are configured to detect and respond to a “coldrunner.” A cold runner can occur when one or a minority of the brakepads are at a lower temperature than the other brake pads. This couldindicate that the brake pad with the lower temperature is not properlyoperating (e.g., is not properly engaging with the brake disk). Variousembodiments can be configured to detect such a cold runner condition andto provide an alarm or other indication, such as to the driver, anotheruser, to a fleet management system, etc. Certain embodiments have beendescribed in which a hot runner determination involves comparingtemperatures between wheels (e.g., compare the temperature of brakepad(s) at a first wheel with the temperature at some or all of the otherwheels). Such a differential comparison between wheels can avoid falsealarm conditions, such as could occur during prolonged breaking wherethe temperature of brake elements at multiple wheels would during normaloperation (no hot runner present) be expected to raise to relativelyhigh temperatures. However, in some other embodiments, a hot runnercondition can be determined based on detecting that an absolutetemperature at one or more wheels is higher than some threshold (e.g.,higher than about 300° C., 350° C., 400° C., 450° C., 500° C., 550° C.,or 600° C.). For instance, the system can detect a hot runner in onesuch implementation when the temperature of a braking device at a wheelexceeds a threshold value for longer than a certain period of time, suchas beyond a period of time that would be expected during even prolongedbraking operation (e.g., more than 10, 20, 30, 60, 90, or 120 seconds).In yet further embodiments, the system can detect a hot runner conditionfor a wheel based on detecting a temperature at a braking device of thatwheel above a threshold value, in combination with using ancillarysensor data. For instance, the system could detect a hot runnercondition where the temperature at a braking device of a given wheel isabove a threshold and where one or more pressure or shear sensors of thebraking device indicate that a braking pressure or torque at thatbraking device is higher by a threshold amount than a braking pressureor torque at a braking device of one or more other wheels.

Certain Terminology

Terms of orientation used herein, such as “top,” “bottom,” “horizontal,”“vertical,” “longitudinal,” “lateral,” and “end” are used in the contextof the illustrated embodiment. However, the present disclosure shouldnot be limited to the illustrated orientation. Indeed, otherorientations are possible and are within the scope of this disclosure.Terms relating to circular shapes as used herein, such as diameter orradius, should be understood not to require perfect circular structures,but rather should be applied to any suitable structure with across-sectional region that can be measured from side-to-side. Termsrelating to shapes generally, such as “circular” or “cylindrical” or“semi-circular” or “semi-cylindrical” or any related or similar terms,are not required to conform strictly to the mathematical definitions ofcircles or cylinders or other structures, but can encompass structuresthat are reasonably close approximations.

Conditional language, such as “can,” “could,” “might,” or “may,” unlessspecifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include or do not include, certain features, elements,and/or steps. Thus, such conditional language is not generally intendedto imply that features, elements, and/or steps are in any way requiredfor one or more embodiments.

Conjunctive language, such as the phrase “at least one of X, Y, and Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to convey that an item, term, etc. may beeither X, Y, or Z. Thus, such conjunctive language is not generallyintended to imply that certain embodiments require the presence of atleast one of X, at least one of Y, and at least one of Z.

The terms “approximately,” “about,” and “substantially” as used hereinrepresent an amount close to the stated amount that still performs adesired function or achieves a desired result. For example, in someembodiments, as the context may permit, the terms “approximately”,“about”, and “substantially” may refer to an amount that is within lessthan or equal to 10% of the stated amount. The term “generally” as usedherein represents a value, amount, or characteristic that predominantlyincludes or tends toward a particular value, amount, or characteristic.As an example, in certain embodiments, as the context may permit, theterm “generally parallel” can refer to something that departs fromexactly parallel by less than or equal to 20 degrees.

Unless otherwise explicitly stated, articles such as “a” or “an” shouldgenerally be interpreted to include one or more described items.Accordingly, phrases such as “a device configured to” are intended toinclude one or more recited devices. Such one or more recited devicescan also be collectively configured to carry out the stated recitations.For example, “a device configured to carry out recitations A, B, and C”can include a first device configured to carry out recitation A workingin conjunction with a second device configured to carry out recitationsB and C.

The terms “comprising,” “including,” “having,” and the like aresynonymous and are used inclusively, in an open-ended fashion, and donot exclude additional elements, features, acts, operations, and soforth. Likewise, the terms “some,” “certain,” and the like aresynonymous and are used in an open-ended fashion. Also, the term “or” isused in its inclusive sense (and not in its exclusive sense) so thatwhen used, for example, to connect a list of elements, the term “or”means one, some, or all of the elements in the list.

Overall, the language of the claims is to be interpreted broadly basedon the language employed in the claims. The language of the claims isnot to be limited to the non-exclusive embodiments and examples that areillustrated and described in this disclosure, or that are discussedduring the prosecution of the application.

Summary

Various hot runner detection and response systems, devices, and methodshave been disclosed in the context of certain embodiments and examplesabove. However, this disclosure extends beyond the specificallydisclosed embodiments to other alternative embodiments and/or uses andobvious modifications and equivalents thereof. In particular, while thesystems, devices, and methods has been described in the context ofillustrative embodiments, certain advantages, features, and aspects ofthe devices, systems, and methods may be realized in a variety of otherapplications. Various features and aspects of the disclosed embodimentscan be combined with or substituted for one another in order to formvarying modes of the devices, systems, and methods. The scope of thisdisclosure should not be limited by the particular disclosed embodimentsdescribed herein.

The hot runner detection and response systems, devices, and methodsdescribed above are susceptible to numerous modifications andvariations, all falling within the scope of the inventive concept;moreover all of the components can be replaced by technically equivalentelements. Additionally, various aspects and features of the embodimentsdescribed can be practiced separately, combined together, or substitutedfor one another. A variety of combination and subcombinations of thedisclosed features and aspects can be made and still fall within thescope of this disclosure. Certain features that are described in thisdisclosure in the context of separate implementations can also beimplemented in combination in a single implementation. Conversely,various features that are described in the context of a singleimplementation can also be implemented in multiple implementationsseparately or in any suitable subcombination. Although features may bedescribed above as acting in certain combinations, one or more featuresfrom a claimed combination can, in some cases, be excised from thecombination, and the combination may be claimed as any subcombination orvariation of any subcombination.

Moreover, while operations may be depicted in the drawings or describedin the specification in a particular order, such operations need not beperformed in the particular order shown or in sequential order, and alloperations need not be performed, to achieve the desirable results.Other operations that are not depicted or described can be incorporatedin the example methods and processes. For example, one or moreadditional operations can be performed before, after, simultaneously, orbetween any of the described operations. Further, the operations may berearranged or reordered in other implementations. Also, the separationof various system components in the implementations described aboveshould not be understood as requiring such separation in allimplementations, and it should be understood that the describedcomponents and systems can generally be integrated together in a singleproduct or packaged into multiple products. Additionally, otherimplementations are within the scope of this disclosure.

Some embodiments have been described in connection with the accompanyingdrawings. The figures are drawn to scale, but such scale should not belimiting, since dimensions and proportions other than what are shown arecontemplated and are within the scope of this disclosure. Distances,angles, etc. are merely illustrative and do not necessarily bear anexact relationship to actual dimensions and layout of the devicesillustrated. Components can be added, removed, and/or rearranged.Further, the disclosure herein of any particular feature, aspect,method, property, characteristic, quality, attribute, element, or thelike in connection with various embodiments can be used in all otherembodiments set forth herein. Additionally, any methods described hereinmay be practiced using any device suitable for performing the recitedsteps.

In summary, various embodiments and examples of hot runner detection andresponse systems, devices, and methods have been disclosed. Although thesystems and methods have been disclosed in the context of thoseembodiments and examples, this disclosure extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or other uses of the embodiments, as well as to certainmodifications and equivalents thereof. This disclosure expresslycontemplates that various features and aspects of the disclosedembodiments can be combined with, or substituted for, one another. Thus,the scope of this disclosure should not be limited by the particularembodiments described above, but should be determined only by a fairreading of the claims that follow.

The following is claimed:
 1. A vehicle system, comprising: a pluralityof braking devices, each respective braking device of the plurality ofbraking devices comprising: a support; a friction material supported bythe support and configured to interface with a rotating part of a brakesystem associated with a wheel of a vehicle; a temperature sensorconfigured to measure a temperature to generate temperaturemeasurements; and a sensor configured to measure one or more of pressureor torque associated with operation of the respective braking device togenerate pressure or torque measurements; and the vehicle system furthercomprising a controller unit configured to: determine based upon one ormore of the temperature measurements that a temperature of at least oneof the plurality of braking devices satisfies a primary thresholdcondition; determine based upon one or more of the temperaturemeasurements that a temperature of at least one other of the pluralityof braking devices does not satisfy the primary threshold condition;determine that a predetermined correlation exists between measuredtemperature of the at least one of the plurality of braking devices andmeasured one or more of pressure or torque of the at least one of theplurality of braking devices, wherein existence of the predeterminedcorrelation indicates an absence of a false hot runner alarm; andsubsequent to determining that the predetermined correlation exists,cause a control signal to be transmitted to a controller of the vehicle.2. The vehicle system of claim 1, wherein the existence of thepredetermined correlation is determined within a predetermined period oftime.
 3. The vehicle system of claim 1, wherein: the controller unit isfurther configured to: compare measured temperature of each brakingdevice to a secondary threshold condition; and activate an alarmindicating an elevated temperature condition in response to determiningthat the temperature of the at least one of the plurality of brakingdevices is greater than the secondary threshold condition and less thanthe primary threshold condition.
 4. The vehicle system of claim 1,wherein receiving the control signal causes the controller to trigger analarm perceptible to a driver of the vehicle.
 5. The vehicle system ofclaim 1, wherein the controller is responsive to the control signal todisplay an alert to a driver on a user interface.
 6. The vehicle systemof claim 1, wherein the control signal triggers an automatic change indriving operation of the vehicle.
 7. The vehicle system of claim 6,wherein the automatic change in driving operation is to slow or stop thevehicle.
 8. The vehicle system of claim 1, further comprising an energyharvesting device configured to convert energy from a motion of thevehicle into electrical energy.
 9. The vehicle system of claim 1,wherein the controller unit determines that an overheating conditionexists at least in part by determining that the temperature of the atleast one of the plurality of braking devices is higher than thetemperature of the at least one other of the plurality of brakingdevices by an amount sufficient to indicate the overheating condition.10. The vehicle system of claim 1, wherein the controller unitdetermines that an overheating condition exists at least in part bydetermining that the temperature of the at least one of the plurality ofbraking devices is at least about 450° C.
 11. The vehicle system ofclaim 1, wherein the controller unit is further configured to determinebased upon one or more of the temperature measurements if thetemperature of each braking device of the plurality of braking devicessatisfies the primary threshold condition during a period in which thevehicle is not braking.
 12. The vehicle system of claim 1, wherein thepredetermined correlation corresponds to a correlation between afunction dependent on the measured temperature of the at least one ofthe plurality of braking devices and a function dependent on themeasured pressure or torque of the at least one braking device of theplurality of braking devices being less than a threshold amount.
 13. Thevehicle system of claim 1, wherein the primary threshold condition isdetermined by: recording a principal measurement of the temperature ofone of the plurality of braking devices; and comparing a plurality oftemperature measurements of the other braking devices against theprincipal measurement, wherein the primary threshold condition issatisfied if one of the plurality of temperature measurements exceedsthe principal measurement.
 14. A method of detecting overheating ofbrakes on a vehicle, the method comprising: measuring a temperature ofat least one of a plurality of braking units by way of a temperaturesensor, wherein each one of the braking units comprises a frictionmaterial supported by a support; measuring one or more of pressure ortorque associated with operation of the at least one of a plurality ofbraking units by way of a sensor; comparing, with an electronic controlunit, the measured temperature with a threshold condition; determiningthat the measured temperature of the at least one of the plurality ofbraking units satisfies the threshold condition; determining that ameasured temperature of at least one other of the braking units does notsatisfy the threshold condition; determining that a predeterminedcorrelation exists between the measured temperature of the at least oneof the plurality of braking units and the measured one or more ofpressure or torque of the at least one of the plurality of brakingunits, wherein existence of the predetermined correlation indicates anabsence of a false overheating condition alarm state; and subsequent todetermining that the predetermined correlation exists, transmitting acontrol signal to a controller of the vehicle.
 15. The method of claim14, further comprising determining whether the measured temperature iswithin a range of temperatures.
 16. The method of claim 14, furthercomprising determining whether the measured temperature is greater thana first temperature threshold for a period of time.
 17. The method ofclaim 16, wherein the method further comprises: acquiring a pressuremeasurement of the at least one of the plurality of braking units, inresponse to the measured temperature of the at least one of theplurality of braking units being greater than the first temperaturethreshold; and accessing a pressure threshold, wherein determiningwhether the predetermined correlation exists further comprisesdetermining, with the electronic control unit, whether measured pressureis less than the pressure threshold.
 18. The method of claim 14, whereinthe method further comprises: determining, with the electronic controlunit, whether an elevated temperature condition exists, wherein theelevated temperature condition exists based on the measured temperatureof the at least one of the plurality of braking units being greater thana second temperature threshold and less than a first temperaturethreshold; and activating an alarm in response to determining that theelevated temperature condition exists.
 19. The method of claim 14,wherein the predetermined correlation corresponds to a correlationbetween a function dependent on the measured temperature of the at leastone of the plurality of braking units and a function dependent on themeasured one or more of pressure or torque of the at least one of theplurality of braking units being less than a threshold amount.
 20. Avehicle system comprising: a plurality of braking devices, eachrespective braking device of the plurality of braking devicescomprising: a support; a friction material supported by the support; atemperature sensor configured to measure a temperature of the respectivebraking device; a sensor configured to measure one or more of pressureor torque associated with operation of the respective braking device;and a controller unit that is configured to: determine based upon thetemperature measured by the temperature sensor of at least one of theplurality of braking devices that a temperature of the at least one ofthe plurality of braking devices satisfies a primary thresholdcondition; determine based upon the temperature measured by thetemperature sensor of at least one other of the plurality of brakingdevices that a temperature of the at least one other of the plurality ofbraking devices does not satisfy the primary threshold condition; anddetermine that a predetermined correlation exists between the measuredtemperature of the at least one of the plurality of braking devices andthe measured pressure or torque of the at least one of the plurality ofbraking devices, wherein existence of the predetermined correlationwithin a predetermined period indicates an absence of a false hot runneralarm.